Editor Charles H. Smith's Note: A letter to the Editor from S. E. Peal, followed by a reply from
Wallace, printed on page 533 of the 4 April 1895 issue of Nature. To link directly to this page,
connect with: http://people.wku.edu/charles.smith/wallace/S511.htm

I trust you will allow me to point out that the drift of my letter on the above subject in
Nature, vol. 1. p. 572, has not been fully apprehended. Hitherto we seem to have no very clear
cases in which we can actually trace the operation of "natural selection." I think, when examined,
this will be found to be an instance.

The spots appear to have arisen in the dog as comparatively recent permanent markings--for
protective purposes--after semi-domestication. As Mr. Worthington G. Smith says, they are not
seen among wild animals allied to the dog.

They appear to have arisen since the original Red Dog--be he Dhole, Pariah, or
Dingo--became pied, and at times black, through domestication. It is only on a black coat that
the tan-spots would be conspicuous, and simulate eyes.

Perhaps Mr. A. R. Wallace may throw light on the matter. The spots seem to be the only
really permanent marking among dogs, and are now being bred out.

S. E. Peal.
Sibsagar, Asam, February 19.

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Mr. Peal's suggestion appears to be a probable one, and is supported by Mr. Worthington
Smith's observations (Nature, vol. 1i. p. 57). The spots may have been protective to the animals
during sleep, causing them to look as if awake. The reason that they do not occur in wild dogs
may be that the latter conceal themselves when sleeping, which the half-domesticated animals
were not able to do.